Electronic relay



Poema Feb. 11, 193s a sneeuwmanc am!! Finn n. Gunmen. minuti", rs., mm1-u Westinghouse Electric & Manufacturing-'Oom- 'I g f v" East Pittsburgh,Pa.,a vcorporation I .vania f my, Pennsyl Application .5, 19.32 y,somma. (ci, irs-'mil ,g L t 1 vme'remis"'1111.this,einem. Preciblecurrent" thmushthe s rld re- Sismi'- thereby setting up therein a'voltage drop My inventiony relates to' electrical` relays and hasparticular relation to relay systems which may bev made responsivetosudden'changes or impulses in the voltage oi' an electrical circuit`without being ailectedby the absolutefmagnitude oi' that voltage.

w A relay system 'possessing impulseresponsive characteristics'is usefulin a number 'ot vapplisirable features and cations, particularly, forexample, in' connectiony with'quick-response excitation systems for dy-.name-electricI machines, especially those oi' the synchronous typewhich may form a part of an altemating-current power system, in that it`permits sudden changes in machine voltage to directly correct themachine excitation without appreciahle delay, the ordinary or moregradual voltage nuctuaticns being takenvcare ofby regulating apparatusoi a conventional type to which the impulse4 relay equipment issupplementary. My invention is directed to the provision of an impulserelay system which possesses the 'de advantages particularizedhereinafter.v

One object of my invention is the provision yof a relay system which islresponsive only to those changes in the voltage of an electricalcircuit which take place with a predetermined su deuness or rapidity:

Another object of my invention isthe provision of an impulse-responsiverelay system which is unail'ected by and independent of the absolutemagnitude ot the voltage of the iniluencing circuit. y

A further object of my invention is the provision. of a relay system ofthe type described which is applicable to either alternating-current ordirect-current circuits.

An additional object of my invention is to provide in a regulatingsystem relay apparatus oi' the type described which is responsive tosudden changes in the voltage oi.' the regulated circuit. l

A still further object of my invention is the provision of an` impulserelay system which .is

particularly suited for application in quick-response excitation systemsfor dynamo-electric machines.`

` In practicing my invention I dispose interme' diate the electricalcircuit and the relay device which is to be actuated upon the occurrenceof sudden changes in the circuit voltage, an electronic tube, in thegrid-controlling circuit `of which is disposed a resistor through ywhicha capacitor is acted upon by a direct-current potential determined bythe circuit voltage. 'Ihe electronic tube is so energized that theoutput thereof, to which the relay device lsesponsive, is independent ofthe absolute magnitude oi' the circuit voltage and `is unaffected bygradual changes therein. A rapid change in the .circuit I UNITED STATESPATENT i which acts to materially change Athe.ve'lec'ztronic' tubeoutput:I to' ,causeigthe goesiredrlay! actuation. 5 wnen'if-isdesiredgthat thefrelaydeyie remain actuated aftertne 'vonage impulsehasisuhsded. a'second electronic `-tilb'eoftthe' gas-lled ordiscontinuous control type.' may be disposed mediate the nrst'tube therelay. n o `10` My invention will bestfbenunderstoodiro'xnthe mllowingJdescription oi yspeciilclfexnbodixnents thereof when' 1n ,comuna-ionaanmete- Flsurefl is 'a diagrammatic'fview of'apparatus 15 and circuitsarranged in 'accordancel ,with .a prei'erred i'orm'I oi my invention.illustrated as forming a part of 'a quickre'sponseexcitaticn systemfor-a dynamo-electric machine, and,

Fig. 2 is a illustration ofthe 20 impulse-relay equipmentfoi Fig.r 1,showing cern tain modiiication's therein. 1 l f Referring to.'` theVand' more particularly tof .liili-l y1,* thereof,V,thedmnulse-.responsive relay' system of my invention ilsv shown as apart 25 0i ya. quick-response excitation system for an,a1

ternating-current dynamo-.electricA machine il which hasarmaturewindings directly connected to the conductors oiathree-phasecircuit I2 and` a iield Il which is supplied with exciting 30 current bymeans ofa directcurrent exciter generatot it. The field winding I'Iofthe exciteru I6 is shown as n being.. energized from a directcurrentcircuit comprising conductors I9 andlll, the'potential dierence betweenwhich ismain- 35 tained substantially constant.

'Ihe machine `Il may be a generator driven at substantially constantspeed by suitable mechanical means (not shown) from which it is desiredto supply a substantially constant voltageto the circuit I2. To adjusttheA magnitude voltage a rheostat 22 is connected in the energizingcn-enit of the exciter.;nem'windingy l'l'.y An increase in the eldwinding .current is eilected by f an adjustment of the. rheostat 22 .inthe re- 45 sistance decreasing direction and the voltage of exciter It,which by increasing the current supplied to machine i'leld winding il,,raises the voltage oi.' machine III.l vIn asimilar manner,"

a rheostat adjustment in the' resistance-increas- 50" ing directionserves to the circuit 'I2'.

` To 'e'ect an automatic adjustment of the rheostat 22 in response tochanges inthe voltage of the circuit' n, a rheostat-operating motor' 'uof 55 suitablelreversible type" is shownv as being'controlled by acontact ldevice 2t an actuating 21 which is` viniiuenced, through apositive phase' sequence network le'qui p ment 30, by the voltage o!polyphase circuit I2. 50

to lower thevoltage supplied Networkll,whlchisthssameasthatshown anddelci'lbed in VU. 8.`Patent N0. 1,571,224,

granted February 2, 1928to C. TQAllcutt, is for the purpose of supplyinga single-phase voltage whichgis dependent upon ali of the phase voltagesof circuit i2 rather than upon any individual onetoinsurethattheregulatorresponseatalltimes be representative of the`elective or average circuit conditions. s.

mnemrknaenernsedthroghvoltasetransformers l2 connected in open delta tothe conductors or' threepbase circuit Il. The sec- Inoperation of theregulating equipment thus fardescribed,whichisshowninahighlysimplinesiforni,whenthevoltageofmachineIlisofl the dired value, contact makingdevice 2l occupies the neutral position shown, and nooperationofrheostatmotorltakesplace. Adecrease belowtbe desiredvalueofthisvoltage causa device 2i to complete through contact member Ran energizing circuit formotor 2l which then opcrates rheostat Il in thevoltage-raising direction to appropriately correct the machine voltage.Similarly, an increase above the desired value e of the machine voltagecauses the completion through contact member L of a motor `energiziingcircuit which adjusts the rheostat Min the voltage-lowering direction.

`The rate of excitation change which a conventional regulator. of thetype described, is capable of electing is relatively slow, and when theregulated machine forms a part of an'alternatingcurrent power systemsudden load demands or other abnormal conditions may result ininstability unless supplementary quick-responsemeansbeprovidedlnthepasttheexpedientsresortedtoforthepurposeofobtainingsuch quick-response excitation havebeen subject to the disadvantage of having a certain amount of delay intheir operation, a typical arrangement (not shown invthedrawing) beingto provide held-circuit resistance shunting relays which are controlledby lthe circuit-influenced contactmaking device (2l) in auch manner thatan excitation change is elected in advance of the necessary adjustmentof the Vmotor-operated rheostat (22). Assuming that when the "lower" vcontacts of the device are engaged, a sudden drop in circuit voltageoccurs, before any excitation correction can be elected it is necessarythat.

thefcontact-carrying arm of the device move to the-other limiting or"raise" position. I'he time required for nsuch movement to be electedrepresents a substantial delay, which delay tbe improved relay -systemof my invention is capable of overcoming. h

The need for a rapid excitation adjustment is more pronounced upon asudden decrease in the machine voltage than upon a sudden increase inthe voltage, the requirement then being to very rapidly mise the macineexcitation, and the impulse-responsive relay system of my invention isillustrated as beingdisposed to fulilll this rewhich aosonov 1theoccurrenceofasuddendecreaseinthevoltage ofcircuit il.

Tne relav l. comprises an actuating winding is supplied with energizingcurrent through a grid-controlled gas-nlled electronic tube Il. The tubeM in turn is -inil'uenced by`a second electronic tube II which ispreferably of time triode vacuum or amplifying type. The tube II isacted upon by a unidirectional voltage de-J rived from a resistor Ilacross which is impressed a unidirectional voltage which. at all times,is proportional to the alternating-current voltage appearing betweenconductors II and I1, and is a measure of the average phase voltage ofcir- `'lhis unidirectional potential is supplied from the conductorsnamed through a transformer Il, having secondary windings Il and i3which feed into a full-wave rectifying tube $2 oi' well-known W, which.together with filtering equipment Il, causes the desired unidirectionalvoltage to appear between conductors li and Il, which, in the mtemshown, yis substantially proportional to the voltage of the polyphasecircuit Il.

Apotentialisimpressedupontheanodeelement il ot the amplifying tube Il ofsuch value astomakeitpoaitive withrespecttothecathode element il. This.potential is supplied from the portion of direct-current energizedresistor Il below tap connection Il through a circuit which includes aresistor I0. The grid element Il of the tube is energized by a negativepotential. from the portion of the direct-current energized resistor Ilabove the tap connection Il through a circuit which includes a resistorM. The magnitudes of these two potentials are so chosen that,

as the voltage between conductors ll andA 56 changes, the potentialcaused to appear between points 'il and 1I, which potential controls thetube M, will remain substantially constant. This is accomplished by thefact that as the anode voltage is, for example, increased the gridvoltage becomes proportionally more negative, increases the repulsion bythe control-grid element of the electrons liberated by the tube cathode,and thus checks the tendencyfor the anode current to rise.

The tube Il, which is of the gas-lilled type. comprises anode andcathode elements t1 and il, respectively, connected in a circuit withthe actuating winding of relay I which is energized from thedirect-current control circuit conductors I! and 2l. When the gridelement 1I) of the tube is maintained at a negative potential, withrespect to the cathode,and exceeds a given critical value, which'inpractice is oi the order of several volts, the tube is maintainednon-coniy ductive and no current ilows between the anode and cathodeelements. However, when the grid bias is reduced below this criticalvalue, conduction between the anode and cathode starts and continuesuntil the anode circuit is interrupted. Thus, in the system of Fig. l,as long as the4 g'rid 10 of tube Il is maintained sufilclently negative,the actuating winding of relay lll will remain unenergized.

In the system ot Fig. l, this negative bias applied to tube Il isdetermined by the excess of the voltage drop through resistor 60 overthat through the portion of direct-current energized resistor Il belowtap 'connection 13. The purpose of 'the inclusion in the circuit of aportion of resistor Il is to compensate for deviations from a constantvalue of the anode current of tube 46 as the voltage across resistor 48changes in a gradual manner. These resistors are` soproportione'd thatnormally this excess will be suiiiciently above the critical value. fortube M to maintain the tube non-conductive. v'II.'husa gradual changethrough a Wide range in the voltage of circuit I2 will be prevented fromeil'ecting the actuation of excitation-raising relay Il.

In order that sudden drops in the voltage of circuit Il-may beinstrumental in actuating relay 48, I provide, in association with thegrid'clrcuit of amplifying-tube 4 8,v al capacitor 18 which is acteduponthrough the resistor 8l by the'voltage which energises the resistor 48.Gradual changes in the magnitude of the potential between conductors Iland- I8 cause only a small capacitor current to ow through the resistor8l setting up therein a voltage drop insumcient to materially unbalancethe proportional change yrelation between the tube grid and anodepotentials. More appreciable changes in the anode current of tube Thus,in operation oi the complete impulseresponsive relay equipment shown inFig. l, a rapid fall in the voltage of circuit I2, by directly loweringthe direct-current potential impressed upon resistor 48, causescapacitor 18 to circulate through resistor 88 a discharge current whichhas a direction indicated by the arrowpwhich discharge current sets upin the resistor a voltage drop in such direction that the value ofnegative bias applied to the grid element 88 ot tube 48 is abnormallyincreased. 'Ihis abnormal increase effects a corresponding reduction inthe magnitude of tube anode current which iiows through resistor 88,with the result that the voltage drop through the resistor is decreasedto a point where the potential impressed upon the grid element I8 oftube Il, through a resistor 18,lsallowed to fall below the criticalvalue .and the tube `ixnmediately becomes conductive.

By virtue of this conduction, the energizing circuit for the actuatingwindingof relay 48 is completed, causing the relay to bias upwardly tothe closed position, a contact member '80 which shunts rheostate 22 fromthe energizing circuit of exciter ileld winding I'I, and thus ,raisesthe excitation of regulated machine Il. T'he tube u remains conductiveuntil the current supplied to iield winding I4 of machine I8 rises to apredetermined value, at which time, a current-responsive relay 82disposed in the held-winding circuit, actuates a contact member 88thereof upwardly toy interrupt the anode circut of tube Il and thuseffect the deenergization of relay III. Such deenergization having beeneffected, the excitation control is returned to the motor-operatedrheostat 22.'

In Fig. 2, I have illustrated a modified form of impulse responsiverelay equipment which fundamentally is the equivalent of that shown anddescribed in connection with Fig. l, but which possesses certainadditional advantages thereover ln that the characteristics of theelectronic tubes utilized therebygiov` not have to be so criticallytaken into account as in the system of' Fig. 1.-'

[n the schematic diagram' of'liig. 2 the directcurrent voltage acrossresistor V48 is, as in the prportiQl t the volta-8691 l i f meansforenergizingvsaid v.ariodeancl grid circuits inl accordance `withpotentlalS kderived from 1 said electrical circuit (in such vznannerthatthe anode-circuit current`- remains substantially consystem ofFig. l,

circuit I2.

The ampliner tubefle is connected to 'resistor 88' Vin suchlxnarincrythatj'the anode current of tube lo does not/change as the regulatedvoltage v changes slowly, `this obtained by selecting sible.

the location of tap 8i so that any change in, tube anode voltage iscompensated for by a proportional change in grid bias voltage. 'I'heresistor 84 and capacitor 18 are connected in a discharge Vcircuit tothe grid element 63 of tube 48 so that i'ordecreasing regulated voltagethe tube grid voltage drop across resistor 68 will decrease, due to thedecreased plate current of-tube'. When the voltage drop V'aucrossresistor elif decreases a voltage drop :will obtain across resistor 8 5,due to the, discharging action of a capacitor 81. The polarity of thevoltage drop across the resistor 85 will be as indicated in the diagram,so that the grid voltage of the gas-lled tube u becomes more positiveand 'causes the tube to break down and energize the winding of the quickresponse shunting relay 40.

The relay 48 remains closed until the directcurrent supply voltage fortube 44 is disconnected by means of contact member 83 of thefield-current limiting relay 82. 'I'he direct-current supply for thetube 44 is supplied from the control circuit conductors I8 and 20,through the voltage divider 80, the negative bias for the tube gridelement, being derived from the right-hand portion of the dividerresistor and the positive anode potential from the left-hand portion.

As above pointed out, the system of Fig. 2, by virtue ofthe modiedscheme of grid control for the tube 4l just described. is more exibleand less responsive to changes in the tube characteristics than is thescheme of Fig. l. Either of the two schemes are capable of responseadjustment by changing the relatlve values of resistor and capacitorelements 6l and 15, or as in the system of Fig. 2, by adiusting themagnitude of voltage which acts upon capacitor I6 through theuse of atap connection 82.

Although the impulse responsive relay equipment of my invention has beenillustrated in quick-response excitation system for a dynamoelect-ricmachine, it will be apparent that itis in no way limited to this oneparticular application, nor is it limited to relay actuation only inresponse to sudden changes in the voltage lowering direction of theregulated circuit. For example, in the event that voltage impulses in `adirect current circuit are to be detected, circuit conductors 55 and 56could be joined directly to the circuit instead of beingsupplied throughthe intermediate apparatus shown in the drawing. It will be apparenttherefore, that the equipment is exceedingly flexible in itsapplication.

A Although I have shown and described certain specific embodimentsof myinvention, I am fully aware that many modications thereof are pos- Myinvention, therefore, is. not to be restricted except insofar as isnecessitated by the prior art andby the' scope of the appended claims.

I claim as myinvention:

l. In combination with a variable-voltage electrical circuit and,l arelay iniiuencedthereby, means for causing the relay to respond tovoltagechange impulses, comprising an electronic tube havingan anode,acathode, and aigrid element,

a circuit including Asaid anodeA and cathode elements for controllingthe actuation of. said relay,

4 gradual cames 1n the electrics; smut voltage. s

` resistor connected `in said grid circuit. and a capacitor connectedthrough said resistor to said electrical circuit for energization inaccordance with the voltage thereof,the effect of said connection beingVto modify the tube grid potential in such manner that when-the saidelectrical-circuit voltage changes at a rapid rate in the voltageidecreasing direction an actuation of the abovementioned relay willresult.`

2.4 In combination, an electrical circuit, an electronic tube, means forso connecting said tube to the circuit that the output current of thetube varies only upon the occurrence of rapid changes in thevoltage ofthe circuit, ay second electronic tube, a relay device connected to saidsecond tube for energization in accordance with the output varies onlyupon the occurrence of rapid changes in the voltage of the circuit, asecond electronic tube, a relay device connected to said second tube forenergization in accordance with the output current thereof, means for imupon said second tube a control potential which maintains itnon-conductive, and means responsive to changes in the output current ofsaid first tube which result from a rapid decrease in said electricalcircuit voltage for modifying said control potential in a manner torendervthe second tube conductive, said last-named means'comprlsing aresistor and a .capacitor connected in series for energization by apotential determined by the output current of said iirst tube, saidresistor being connected tomodify the control potential applied to thesecond tube.

4. In combination with a relay and a source of potential, means forcausing said relay to be responsive to sudden changes in thepotential-decreasing direction in the magnitude `oi' said po- `tentialand to be unailected by tbe absolute value thereof comprising anelectronic tube, a circuit connecting the relay to said tube in a mannerto eiiect actuation of the relay when the tube ris rendered conductive.a second electronic tube connected to render said. nrst tube conductivethe output of the second tube exceeds a given value, said second tubebeing oi the triodetype ,l and having associated therewith anode andgrid circuits, means for so connecting said circuits to said source ofpotential that the tube output remains below the said given valuethroughout a wide range of steady state values of the potential, aresistor connected in the said tube grid circuit, and a capacitorenergized by the potential ofsaid source through a circuit whichincludes said resistor, the eflect of said resistor and capacitor whenso connected being to cause the tube output to increase when thepotential ofV said source decreases ata rapid rate.

5. In combination, an electrical circuit, an electronic tube havinganode and grid elements connected to be energized in accordancewithpotentials derived from said circuit. said connection being such thatvariations in the voltage of the cir` cuit which produce changes in thenegative direcaoscnov tion in the potential supplied to the tube gridalso produce changes inthe positive direction in the potential suppliedto the tube anode. and vice versa, to thereby cause the anode current ofthe tube to be independent of the steady state magnitude of said circuitvoltage. a relay, means responsive to changes in said tube anode currentfor controlling the actuation of said relay, and means responsive torapid changes in said circuit voltage' in the voltage-decreasingdirection for so. moditying the potentiall impressed upon the gridelement of the tube as to produce a relay-actuating change in the tubeanode current. u

Vii. In combination, an electrical circuit, an electronic'tube havinganode and grid elements connected tobe energized ,in accordance withpotentials derived from said circuit, said connection *being such thatvariations in the voltage of the circuit produce changes in oppositedirections in said two potentials to thereby cause the anode current ofthe tube to be independent of the steady state magnitude of said circuitvoltagepa relay, means responsive to changes in said tube anode currentfor controlling the actuation of said relay, and means, comprising aresistor connected intermediate the tube grid element and its source ofpotential and a capacitor energized through said resistor by a measureof said circuit voltage, for causing rapid changes in said circuitvoltage in the voltage-decreasing direction to so modify the tube gridpotential as to produce a relay-actuating change in the tube anodecurrent.

7. Means for causing a relay device to be responsive to sudden changesin a decreasing direction inthe voltage of a direct-current circuitcomprising, in combination, an electronic tube having anode and gridelements connected to be energized in accordance with potentials derivedfrom said circuit, said connection being such that the anode current ofthe tube will be maintained sub- I stantially constant as the voltage o!said circuit gradually changes, a relay, means responsive to changes insaid anode current for controlling the actuation of said relay, andmeans, comprising a series-connected capacitor and resistor energized bya measure of said circuit voltage, adapted to vary said tube anodecurrent upon the occurrence of a predeterminedly rapid change in saiddecreasing direction in the magnitude. f said circuit voltage, saidresistor being connected between 1 the tube grid element and its sourceof potential and acting to modify the voltage impressed upon said gridin accordance with the current which the capacitor allows to passthrough the resistor.

8. In combination, an alternating-current cirl cuit, an electronic tubehaving anode and grid elements, rectifying, means for supplying fromsaid alternating-current circuit direct-current potentials to said tubeelements,` said potentials being so interdependent that the anodecurrent of the l tube will be maintained substantially constant and ofan appreciable magnitude asthe voltage of the alternating-currentcircuit gradually changes, arelay. means responsive to predeterminedchanges in said anode current for controlf ling the actuation of saidrelay. and means for so predeterminedly varylng'said anode current inaccordance with the rate of change of said circuit voltage in adecreasing direction, said last-named means comprising a resistorconnected intermediate the tube grid element and its source of potentialand a capacitor energized through said resistor by a direct-currentpotential supplied from the circuit through said rectifylng means.

- FINN H. GULLIKSEN.

